Alert: Unconfirmed reports of explosives at four sites on campus: Science Center, Thayer, Sever and Emerson. Evacuate those buildings now.
Harvard University issued that warning Monday morning, and police swarmed the Cambridge, Mass., campus for several hours. The bomb threat proved false, but Harvard was not alone in seeing its final exams disrupted: That afternoon, the University of Massachusetts Boston evacuated a building after reports of a gunman, which also turned out to be unfounded.
For college students across the country, such warnings come with disturbing regularity, driven by hyper-vigilance and federal requirements that officials rapidly report possible threats.
Last week, American University in Washington was locked down while police sought a supposed gunman — who turned out to be an off-duty police officer.
In early November, SWAT teams searched Central Connecticut State University for a masked man with a gun and a sword. He turned out to be a student in a Halloween costume, and he was charged with a misdemeanor.
On Dec. 3, the University of New Haven in West Haven, Conn., was paralyzed by a 911 call about a possible gunman. This time, the suspect turned out to be a student armed with two pistols who also had an illegal assault rifle in his SUV, 2,700 rounds of ammunition in his padlocked bedroom and news clippings about mass shootings, police said. He faces weapons charges.
Within the last month, threats and worried 911 calls have sent tens of thousands of students into hiding in dorms and classrooms at campuses as diverse as Yale University, North Carolina Central University and Martin Methodist College in Pulaski, Tenn.
The spate of campuswide lockdowns has drawn attention to the practice, which security officials say they increasingly rely on.
Over the last year, high schools, middle schools and even elementary schools have been crime scenes. Just last week a student at Arapahoe High School in Centennial, Colo., critically wounded one girl before killing himself.
Mayors Against Illegal Guns, a gun control advocacy group, says there have been 28 instances in which someone fired or threatened to fire a gun on school grounds in the year since the rampage at Sandy Hook Elementary School in Newtown, Conn. Eight of those incidents occurred at colleges, the group said.
Many students who arrive at college campuses today are familiar with lockdown drills, which they learn in high school. But some critics say lockdowns are heavy-handed when used on sprawling, hard-to-secure college campuses, where student life is much less regulated, crime rates tend to be low, and mass shootings remain extremely rare.
"I don't think there's any greater level of danger, but our response to it is much different than it used to be," Northeastern University criminology professor James Alan Fox said. "You've put colleges in a position where they have to err on the side of caution, and unfortunately they err a lot on the side of caution."
College police chiefs note that federal law requires them to promptly notify campuses of possible threats, sometimes before investigators have time to learn whether the threats are credible.
The Clery Act, originally passed in 1990, requires colleges and universities participating in federal financial aid programs to track and report crimes on and near campus. Penalties include up to $35,000 per violation and suspension of the school's federal financial aid programs.
Congress strengthened the law's campuswide alert requirements after the 2007 Virginia Tech massacre, in which the shooter killed 32 people. The university was fined and sued for not notifying students quickly.
Campus police chiefs say such high-profile shootings also have made staff and students more vigilant and likely to report suspicious activity.
"One of the most common calls is the 'man with a gun,'" said Cal State Northridge Police Chief Anne P. Glavin, referring to incidents in which somebody claims to have spotted someone with a weapon. "Before you had this federal law, 'man with a gun' happened too, just nobody paid attention to it. But now we have these emergency notification systems, they're very public. People's phones get paged; text messaging clicks in."
The seeming surge of lockdowns over the last year may be amplified by social media.
Glavin, who until recently was also president of the International Assn. of Campus Law Enforcement Administrators, added: "When those things start to hit, and you use Facebook and Twitter and all of that, it's out there, and everybody and their brother and the press and the whole world knows it."
California has not been immune to the trend. San Jose State University was placed on a two-hour lockdown in October after reports of a gunman on campus, which proved false. In June, a man killed his father and brother and then fatally shot three people at Santa Monica College before police killed him.